It is not surprising that we found the future fascinating; after all, we are all going there. But the future is never what it used to be and it is said that predictions are always difficult, especially those dealing with the future.
Nevertheless, it is possible to study the future, which is something different from predicting it. It is an exercise called "scenario building". Here, let me try a telescopic sweep of scenario building that starts from the remote past and takes us to the remote future over a total range of 20 billion years. While the past is what it was, our future bifurcates into two scenarios; one "good" and the other "bad", all depending on what we'll be doing in the coming years.

The past 10 billion years

- 10 billion years ago. The universe is young, it only has less than four billion years. But it already looks the way it will be for many billion years: galaxies, stars, planets, black holes and much more.

- 1 billion years ago. From the debris of ancient supernovas, the solar system has formed around a second generation star, the Sun, about 4.5 billion years ago. The planets that form the system are not very different from those we see today. Earthhas with blue oceans, white clouds and dark brown continents. But there are no plants or animals on the continents, nor fish in the water. Life is all unicellular in the oceans, but its activity has already changed a lot of things: the presence of oxygen in the atmosphere is a result of the ongoing photosynthesis activity.

- 100 million years ago. Plenty of things have been happening on planet Earth. Starting about 550 million years ago, perhaps as a result of the ice age known as "snowball Earth" multicellular life forms have appeared. First, only in the oceans; then, about 400 million years ago, life has colonized the surfaces of the continents creating lush forests and large animals that have populated the Earth for hundreds of millions of years of years. That wasn't uneventful, though. Life nearly went extinct when, 245 million years ago, a giant volcanic eruption in the region we call Siberia today generated the largest known extinction of Earth's history. But the biosphere managed to survive and regrow into the cretaceous period, the age of Dinosaurs.

- 10 million years ago. Dinosaurs have disappeared. They have been wiped out by a new mass extinction, caused probably by a giant asteroid which hit the Earth 65 million years ago. Again, the biosphere has survived and now it prospers again, populated with mammals and birds; including primates. We are in the Miocene period and the Earth has been cooling down over a period of several million years, possibly as the result of the Indian subcontinent having hit Asia and created the Himalayas. That has favored CO2 removal from the atmosphere by weathering and has lowered temperatures. Icecaps have formed both at the North and the South poles for the first time in several hundred million years.

- 1 million years ago. The Earth has considerably cooled down during the period that we call "Pleistocene" and it is now undergoing a series of ice ages and interglacials. Ice ages last for tens of thousands of years, whereas the interglacials are relatively short hot spells, a few thousands of years long. These climatic oscillations are perhaps the element that stimulate the evolution of some primate species which have developed bipedal locomotion. One million years ago, homo erectus and homo abilis can use fire and make simple stone tools.

- 100.000 years ago. The glacial/interglacial cycles continue. The hot spell called the "Eemian" period, about 114,000 years ago, has been short lived and has given way to one of the harshest known glaciations of the recent Earth's history. But humans can survive these conditions. In Europe, the Neanderthals rule while the species that we call "homo sapiens" already exists in Africa.

- 10.000 years ago. The ice age ends abruptly to give rise to a new interglacial; the period that we call "Holocene." The Neanderthals have disappeared, pushed out of the edge of survival by their "Sapiens" competitors. Climate stabilizes enough for humans to start to practice agriculture in the fertile valleys along the tropical region of Africa and Eurasia, from Egypt to China.

- 1000 years ago. The agricultural age has given rise to the age of empires, fighting for domination of large geographical areas. The human population has been rapidly growing, with the start of a series of cycles of growth and collapse that derive from the overexploitation of the fertile soil. 1000 years ago, the Western World is coming back from one of these periodic collapses and is expanding again during the period we call "Middle Ages".

- 100 years ago. The age of coal has started and has been ongoing for at least two centuries. With it, the industrial revolution has come. Coal and crude oil are the fuels that create a tremendous expansion of humankind in numbers and power. 100 years ago, there are already more than a billion humans on the planet and the population is rapidly heading for the two billion mark. Pollution is still a minor problem that goes largely unrecognized. The concentration of carbon dioxide in the atmosphere has been increasing to near 300 ppm over the 270 ppm which has been the pre-industrial age. This fact is noted by some human scientists, but the long term consequences are not understood.

- 10 years ago. The fossil fuels which have created the industrial age are starting to show signs of depletion and the same is true also for most mineral commodities. The attempt to replace fossil fuels with uranium has not been successful because of the difficulties involved in controlling the technology. Energy production is still increasing, but it shows signs of slowing down. The human population has reached 6 billion and keeps growing, but at reduced rates of growth. The Earth's agricultural system is in full overshoot and the population can only be fed by means of an agricultural-industrial complex based on fossil fuels. The concentration of CO2 in the atmosphere has been growing fast and is now about 370 ppm. Global temperatures have been rising, too, and the problem of global warming has been recognized and considerable efforts are being made to reduce the emission of CO2 and of other greenhouse gases.

- Today. The world's industrial system seems to be close to stopping its growth and the financial system has been going through a series of collapses. The production of crude oil has been stable during the past few years; but the overall energy production is still increasing because of the rapid growth of coal production. The political situation is chaotic, with continuously erupting minor wars. The human population has reached seven billion. The climate system seems to be on the verge of collapse, with a rapid increase in natural catastrophes all over the world and the near disappearance of the ice cap at the North Pole.The concentration of CO2 in the atmosphere is almost 400 ppm and keeps increasing.

The future in two scenarios 1.The "bad" scenario.

- 10 years from now. In 2020, the production of "conventional" crude oil has started a historical trend of decline, but an enormous effort has been made to replace it by liquids produced using non conventional sources. Tar sands, shale oil and other "heavy" oil sources, as well as biofuels are being produced in amounts sufficient to stave off the decline. Natural gas production is in decline, but large investments in "shale gas" have so far avoided collapse. Uranium, too has become scarce and several countries which don't have national resources have been forced to close down some of their nuclear plants.

These trends are partially compensated by the still increasing production of coal; which is also increasingly used to produce liquid fuels and other chemicals that once had been obtained from oil. The growth of renewable energy has stalled: there are no more resources to invest in research and development in new technologies and new plants, while a propaganda campaign financed by the oil industry has convinced the public that renewables produce no useful energy and are harmful for the environment.

Another propaganda campaign financed by the same lobbies has stopped all attempts of reducing the emissions of greenhouse gases. As a result, agriculture has been devastated by climate change and by the high costs of fertilizers and mechanization. The human population starts an epochal reversal of its growing trend, decimated also in reason of the increasing fraction of fertile land which is dedicated to biofuels.

- 100 years from now. In 2100, the human economic system has collapsed and the size of the economy is now a small fraction of what it had been at the beginning of the 21st century. Resource depletion has destroyed most of the industrial system, while climate change and the associated desertification - coupled with the destruction of the fertile soil - have reduced agriculture to a pale shadow of the industrial enterprise it had become. The collapse of agriculture has caused a corresponding population collapse; now under one billion people.

Most tropical areas have been abandoned because global warming has made them too hot to be habitable by human beings. The rise in sea level caused by global warming has forced the abandonment of a large number of coastal cities, with incalculable economic damage. The economy of the planet has been further weakened by giant storms and climate disasters which have hit about every inhabited place.

Crude oil is not extracted any more in significant amounts and where there still exist gas resources, it is impossible to transport them at long distances because of the decay of the pipeline network and of the flooding of the ports. Only coal is still being extracted and coal fired plants maintain electric power for a reduced industrial activity in several regions of of the North of the planet. Labrador, Alaska, Scandinavia and Northern Siberia see the presence of remnants of the industrial society. Using coal liquefaction, it is still possible to obtain liquid fuels, mostly used for military purposes. The Earth still sees tanks and planes that exchange gunfire against each other.

- 1000 years from now.The industrial society is a thing of the past. Human caused global warming has generated the release of methane hydrates which have created even more warming. The stopping of the Oceanic thermohaline currents has transformed most of the planet into a hot desert. Almost all large mammals are extinct. Humans survive only in the extreme fringes of land in the North of the planet and in the South, mainly in Patagonia.

For the first time in history, small tribes of humans live on the rapidly de-frosting fringes of the Antarctic continent, living mainly of fishing. In some areas, it is still possible to extract coal and use it for a simple metallurgy that uses the remains of the metals that the 20th century civilization has left. Human being are reduced to a few million people individuals who keep battling each other using old muskets and occasional cannons.

- 10.000 years from now. Planet Earth is still reeling from the wave of global warming that had started many thousands of years before. The atmosphere still contains large amounts of greenhouse gases generated by human activity and by the release of methane hydrates. The continents are mostly deserts, and the same is true for oceans, reduced to marine deserts by the lack of oxygenating currents. Greenland is nearly ice-free and that's true also for Antarctica, which has lost most of its ice. Human beings are extinct, together with most vertebrates and trees. Only bushes and small size land vertebrates survive in the remote northern and southern fringes of continents.

- 100.000 from now. The planet is showing signs of recovery. Temperatures have stabilized and silicate erosion have removed a large fraction of the carbon dioxide that had accumulated in the atmosphere. Land plants and trees show some sign of returning.

- 1 milion years from now. The planet has partly recovered. The planetary tectonic cycles have re-absorbed most of the CO2 which had created the great burst of warming of long before. Temperature has gone down rapidly and polar ice caps have returned. The return of ice has restarted the thermohaline currents: oceanic waters are oxygenated again. Life - those species that had survived the warming disaster - are thriving again and re-colonizing the tropical deserts - which are fast disappearing.

- 10 million years from now. Earth is again the lush blue-green planet it used to be, full of life, animals and forests. From the survivors of the great warming, a new explosion of life has been generated. There are again large herbivores and carnivores, as well as large trees, even though none of them looks like the creatures which had populated the Earth before the catastrophe. In Africa, some creatures start using chipped stones for hunting. In time, they develop the ability of creating fire and of building stone structures. They develop agriculture, sea-going ships and ways of recording their thoughts using symbols. But they never develop an industrial civilization for lack of fossil fuels, all burned by humans millions of years before them.

- 100 milion years from now. Planet Earth is again under stress. The gradual increase in solar irradiation is pushing climate towards a new hot era. The same effect is generated by the gradual formation of a new supercontinent generated by continental drift. Most of the land becomes a desert - all intelligent creatures disappear. There starts a general decline of vertebrates, unable to survive in a progressively hotter planet.

- 1 billion years from now. The Earth has been sterilized by the increasing solar heat. Just traces of single celled life still survive underground.

- 10 billion years from now. The sun has expanded and it has become so large that it has absorbed and destroyed the Earth. Then, it has collapsed in a white dwarf. The galaxy and the whole universe move slowly to extinction with the running down of the energy generated by the primeval big bang.

2.The "good" scenario

- Ten years from now. In 2020, fossil fuel depletion has generated a global decline of production. That, in turn, has led to international treaties directed to ease the replacement of fossil fuels with renewable energy. Treaties are also enacted with the purpose of minimizing the use of coal. The production and the use of biofuels is forbidden everywhere and treaties force producers to direct all the agricultural production towards food for humans.

The existing nuclear plants make full use of the uranium in the warheads that had been accumulated during the cold war. Research on nuclear fusion continues, with the hope that it will provide useful energy in 50 years. Even with these actions, global warming continues and agriculture is badly damaged by droughts and erosion. Population growth stops and widespread famines occur. Governments enact fertility reduction measures in order to contain population. Nevertheless, the economy does not show signs of collapse, stimulated by the demand for renewable plants.

- A hundred years from now. The measures taken at the beginning of the 21st century have borne fruit. Now, almost 1% of the surface of the planet is covered by solar panels of the latest generations which produce energy with efficiency of the order of 50%. In the north, wind energy is used, as well as energy from ocean currents, tides, and waves. The production of renewable electrical energy keeps growing and it has surpassed anything that was done in the past using primitive technologies based on fossil fuels. No such fuels are extracted any longer and doing so is considered a crime punishable with re-education.

The industrial economy is undergoing rapid changes, moving to abandon the exploitation of dwindling resources of rare metals, using the abundant energy available to exploit the abundant elements of the Earth's crust. The human society is now completely based on electric energy, also for transportation. Electric vehicles move along roads and rails, electric ships move across the oceans and electric airship navigate the air. The last nuclear fission plants have been closed for lack of uranium fuel around 2050, they were not needed any more, anyway. Research on nuclear fusion continues with the hope that it will provide usable energy in 50 years.

Despite the good performance of the economy, the ecosystem is still under heavy stress because of the large amounts of greenhouse gases emitted into the atmosphere during the past centuries. Agriculture is still reeling from the damage done by erosion and climate change. The human population is in rapid, but controlled, decline under the demographic measures enacted by governments. It is now less than 4 billion humans and famines are a thing of the past. With the returning prosperity, humans are restarting the exploration of space that they were forced to abandon at the start of the 21st century.

- 1000 years from now. In the year 3000 A.D. the ecosystems of the planet have completely recovered from the damage done by human activities during the second millennium. The planet's climate is now fully under human control. A sophisticated planetary control system manages solar irradiation by means of space mirrors and the concentration of greenhouse gases by means of CO2 absorbing/desorbing plants.

The planet is managed as a giant garden, optimizing its biological productivity. The Sahara desert is now a forest and the thermohaline currents pump oxygen in the northern regions, full of life of all kinds. The solar and wind plants used during the previous millennium have been mostly dismantled, although some are still kept as a memory of the old times. Most of the energy used by humankind is now generated by space stations which capture solar energy and beam it to the ground in forms easily usable by humans. Research in controlled fusion energy continues with the hope that it will produce usable energy in 500 years.

Humans are now less than one billion, they have optimized both their numbers and their energy use and they need enormously less than they had needed in the more turbulent ages of one thousand years before. The development of artificial intelligence is in full swing and practically all tasks that once had been in the hands of humans is now in the "hands" of sophisticated robotic systems. These robots have colonized the solar system and humans now live in underground cities on the Moon. The new planetary intelligence starts considering the idea of terraforming Mars and Venus. The first antimatter powered interstellar spaceships have started their travel to far away stars.

- 10.000 years from now. There are now less than a billion human beings on Earth who live in splendid cities immersed in the lush forest that the planet has become. Some of them work as a hobby on controlled nuclear fusion which they hope will produce usable energy in a few thousand years.
The New Intelligence has now started terraforming Mars. It involves similar methods as those used for controlling the Earth's climate: giant mirrors and CO2 producing plants that control the Martian atmosphere, increasing its pressure and temperature. The terraforming of Venus has also started with similar methods: giant screens that lower the planetary temperatures and immense flying plants that transform CO2 into oxygen and solid carbon.

That will take a lot of time, but the New Intelligence is patient. It is also creating new races of solid state beings living on the asteroids and orbiting around the Sun. The exploration of the galaxy is in progress, with spaceships from the solar system now reaching a "sphere" of about a thousand light years from the sun.

- 100.000 years from now. About 500 million humans live on Earth - mostly engaged in art, contemplation, and living full human lives. Nobody knows any longer what "controlled nuclear fusion" could mean. Mars is now colonized by Earth's plants, which are helping to create an atmosphere suitable for life; it is now a green planet, covered with oceans and lush forests. Several million human beings live there. The temperature of Venus has been considerably lowered, although still not enough for life to take hold of its surface. The exploration of the galaxy is in full swing. Other galactic intelligences are encountered.

- A million years from now. Venus, Earth and Mars are now lush and green; all three full of life. Mercury has been dismantled to provide material for transforming the solar system into a single intelligence system that links a series of creatures. There are statites orbiting around the sun, solid state lifeforms living on asteroids and remote moons, ultra-resistent creatures engineered to live in the thick atmosphere of Jupiter and of the other giant planets. Humans, living on the green planets, have become part of this giant solar network. The other extreme of the Galaxy has been now reached by probes coming from the solar system.

- 10 milion years from now. The New Intelligence is expanding over the Galaxy. The Green planets are now the place of evolution tests and the Neanderthals now live on Mars, whereas dinosaurs have been recreated on a Venus where the planetary control system has recreated conditions similar to those of the Jurassic on Earth.

- In 100 million years from now. Controlling temperatures over the three green planets of the Solar System has become a complex task because of the increasing solar radiation. Mirrors are not enough any more and it has been necessary to move the planets farther away from the sun; which is now the preferred system for climate control. The statites that form the main part of the solar intelligence now surround the sun almost completely in a series of concentric spheres.

- In a billion years from now. The solar radiation has increased so much that it has been necessary to move the green planets very far away. One year lasts now as 50 of the "natural" Earth years as they were long before. But these are no problems for the Solar Intelligence, now just a small part of the Galactic intelligence. The three green planets are three jewels of the Solar System.

- In ten billion years from now. The sun has collapsed in a weak white dwarf and all the planets that orbit around it are now frozen to death. The Galaxy has lost most of its suns and the universe is entering its last stage of expansion which will lead it to become a frozen darkness. The Galactic Intelligence looks at a nearly dark galaxy. It is now the moment. The Intelligence says, "Let there be light" And there is light..